Project Summary/Abstract: In vivo Handheld Coherent Raman Scattering (CRS) Microscopy for Glioma Imaging Gliomas are characterized by an infiltrative pattern of growth. However, current clinical imaging modalities are not capable of detecting the infiltrating margins of gliom. In addition, glioma infiltration is difficult to model in experimental systems. An imaging method capable of directly imaging the spread of neoplastic cells into normal brain, in situ, would: (1) contribute greatly to the understanding of glioma infiltration, and (2) improve the accuracy of glioma surgery. Here we propose the translation of coherent Raman scattering (CRS) microscopy as a means of imaging human gliomas. The laboratory of Prof. Sunney Xie has pioneered CRS microscopy and applied it to the label----free, chemical imaging of living cells and tissues. Recent work on CRS has culminated in the discovery of stimulated Raman scattering (SRS) microscopy and demonstration of in vivo human tissue imaging. SRS enables high----resolution, histologic imaging of biological specimens based on the distribution of macromolecular components such as lipids, proteins, and DNA. Because it relies on intrinsic tissue components for contrast, SRS imaging is free of the limitations of dye----based methods for visualizing tissue architecture. In addition, SRS microscopy is uniquely well----suited for in vivo, in situ imaging because it can be performed, based on back----scattering of the excitation signal, in real----time (imaging speed up to 30 frames per sec). Consequently, SRS microscopy creates the possibility of studying key aspects of glioma biology in patients, such as invasion, that are difficult to recreate in animal models. Moreover, SRS microscopy may ultimately become a useful tool for improving surgical accuracy by enabling detection of residual tumor on a cellular level during surgery. We have recently demonstrated that a traditional laboratory----style SRS microscope can accurately image glioblastoma infiltration in fresh, unprocessed human surgical specimens ex vivo and in vivo in human glioblastoma xenograft models. Now we intend to draw on the strength of a multidisciplinary team of academic, clinical, and industrial partners, as well as the University of Michigan Investigator Assistance Program, to achieve the long----term goal of the research proposed here: the development of a handheld clinical SRS system that can be used during surgery to better understand and treat gliomas. The goal of this proposal is to develop and validate an SRS microscopy system for use in human tissues and animal models in a manner appropriate for future regulatory approval (IDE).